Shades of Clouseau, but this still looks like I’d enjoy it way too much.
Carnival of Evolution #17 at Adaptive Complexity
Over at Adaptive Complexity, Michael White has just compiled the 17th monthly Carnival of Evolution. Marking the 150th anniversary of the publication of The Origin of Species (November, 1859), Michael structures submitted posts into a “virtual voyage of the Beagle.” Topics range from the sexual habits of our ape-like ancestors* to a highly optimistic study predicting that the frequency of the creationist meme in the United States will drop to 0% by 2050.
* Which habits might, I think, explain why we never invite them round to tea.
Berry Go Round #21 at Beetles in the Bush
Ted MacRae has a fine round-up* for the 21st monthly Berry Go Round, the bontanical blog carnival. And he notes that BGR needs a badge. Must … resist … urge … to spend afternoon futzing with Inkscape.
*Including a set of nested footnotes that would make David Foster Wallace blush.
I want to teach this course
Via io9: BIOL 103, “Biology in Science Fiction”, at Kenyon College. Sure, the lesson on tribbles is probably just about density-dependent population growth. But it’s a lesson on tribbles.
Endless forms: Oral sex by fruit bats
One of those scientific papers that seems to have been written with the blogosphere in mind: biologists have just published records of fellatio by the fruit bat Cynopterus sphinx. Apparently C. sphinx females are pretty flexible — they lick their mate’s penis during copulation, which evidently induces him to stay in longer (see the graph below, with drawing). The authors offer a handful of non-mutually-exclusive hypotheses for the adaptive benefit of the behavior, ranging from lubrication to increased fertilization efficiency. The full text is available for free at PLoS ONE, if you’re up for some hot-and-heavy behavioral observations.
Update: In a more in-depth post over at Boing-Boing, Maggie Koerth-Baker wonders why there needs to be an adaptive purpose for a pleasurable behavior (there doesn’t, as far as I’m concerned), and points out that there’s also a video in the supporting information. Which video has some totally unscientific background music.
Reference
Tan, M., Jones, G., Zhu, G., Ye, J., Hong, T., Zhou, S., Zhang, S., & Zhang, L. (2009). Fellatio by fruit bats prolongs copulation time PLoS ONE, 4 (10) DOI: 10.1371/journal.pone.0007595
How to synchronize flowering without really trying
One way plants can gain an advantage in their dealings with pollinators, seed dispersers, or herbivores is to act collectively. For instance, when oak trees husband their resources for an extra-big crop of acorns every few years instead of spreading them out, acorn-eating rodents are overwhelmed by the bumper crop, and more likely to miss some, or even forget some of the nuts they cache. These benefits of synchronized mass seed production, or “masting,” are straightforward, but how it happens is less clear. A paper in the latest issue of Ecology Letters has an answer — synchronization happens accidentally [$-a].
When Dan Janzen first described masting as an adaptation in plants’ coevolution with seed predators, he proposed that “an internal physiological system” [$-a] acted as a timer between masting events, with masting ultimately triggered by weather conditions. However, mathematical models have suggested a different possibility, the “resource-budget hypothesis:” that masting synchronization arises through an interaction of resource and pollen limitation [$-a].
Resource limitation works in concert with pollen limitation by catching plants at two stages of the seed-production process. First, if the resources required for seed production are more than can be accumulated in a single year, or if the availability of resources varies from year to year, then some years will be spent building up reserves instead of producing flowers. When reserves are built up, seed production is limited by the availability of pollen to fertilize flowers. Plants that flower when most of the rest of the population doesn’t will fail to set much seed, so they’ll have reserves to make seeds in the next year. This doesn’t require Janzen’s “internal physiological system” for the plants to synchronize, although such a system might evolve to reduce the likelihood of wasting resources by flowering out of synch.
The new paper tests this model in populations of a western U.S. wildflower, Astralagus scaphoides, which flowers at high frequency every alternate year. The authors prevented seed production in the plants by removing their flowers, either in a “press” of three years in a row or in a single “pulse” during one high-flowering year. The plants’ response to these treatments would reveal the role of resource and pollen limitation in synchronizing seed production.
If resource depletion after fruit set prevents reproduction in successive years, we predicted that ‘press’ plants would flower more than control plants every year, as they were never allowed to set fruit. We predicted that ‘pulse’ plants would flower again in 2006, but not set fruit due to density-dependent pollen limitation in a low-flowering year.
The authors also measured the sugars stored in the roots of plants collected before and after flowering in a high-flowering year.
The resource-budget hypothesis worked. Plants prevented from setting seed were forced out of synch with the rest of the population. “Pulse” plants flowered the year after treatment, but because few other plants did, they received little pollen and set little seed. They then had resources to flower yet another year, with the rest of the population this time, and set much more seed, depleting their reserves and bringing them back into synch. “Press” plants continued to flower at high rates each year, as long as they were prevented from setting any seed. Sugar levels built up in the tested roots during non-flowering years, and dropped after high-flowering years.
So masting arises as an emergent result of two limitations acting on plants — the resources needed to make seed, and good access to pollen. A couple of simple rules lead, undirected, to an ordered system that affects entire natural communities.
References
Crone, E., Miller, E., & Sala, A. (2009). How do plants know when other plants are flowering? Resource depletion, pollen limitation and mast-seeding in a perennial wildflower. Ecology Letters, 12 (11), 1119-26 DOI: 10.1111/j.1461-0248.2009.01365.x
Janzen, D. (1971). Seed predation by animals Ann. Rev. Ecol. Syst., 2 (1), 465-92 DOI: 10.1146/annurev.es.02.110171.002341
Janzen, D. (1976). Why bamboos wait so long to flower Ann. Rev. Ecol. Syst., 7 (1), 347-91 DOI: 10.1146/annurev.es.07.110176.002023
Satake, A., & Iwasa, Y. (2000). Pollen coupling of forest trees: Forming synchronized and periodic reproduction out of chaos. J. Theoretical Biol., 203 (2), 63-84 DOI: 10.1006/jtbi.1999.1066
Someone’s on the ball
The website for Evolution2010 is already online! I really like the logo. The site design looks familiar, and good for the organizers for not wasting time to re-evolve the camera eye, say I. Portland is going to be a great location, I think — my experience is that Evolution meetings are largely remembered by the quality of beer available, which should be hard to get wrong in that town.
An important distinction
Courtesy Slacktivist:
Here I would remind us, again, of Wendell Berry’s distinction between religion and superstition. Religion, Berry said, is belief in something which cannot be disproved. Superstition, on the other hand, is belief in something that has been disproved. The former can be reasonable, the latter cannot. For all of Bill Maher’s railing against religion as “mere superstition,” it seems he doesn’t understand either of those ideas. His latest anti-vaccine, anti-medicine, anti-science crusade is superstitious nonsense. It’s religulous.
The first church of taking offense
Heard about R. Crumb’s comic-book adaptation of Genesis? The Slog passes this along from the Daily Telegraph:
“It is turning the Bible into titillation,” said Mike Judge, of the Christian Institute, a religious think-tank. “It seems wholly inappropriate for what is essentially God’s rescue plan for mankind.
“If you are going to publish your own version of the Bible it must be done with a great deal of sensitivity. The Bible is a very important text to many many people and should be treated with the respect it deserves.”
Thing is, Crumb’s adaptation is an entirely straight-faced illustration of the text. (Check out NPR’s excerpt, if you want to see for yourself.) So, yes, Adam and Eve are naked, and Lot has incestuous (and unwilling) sex with his daughters. But these are straight out of the text! That’s right: a Christian “think-tank” is objecting to the very concept of illustrating the Bible. Slacktivist is right, in spades.
Fearmongering for good?
Medical thriller specialist Robin Cook outlines the plot of a book about the catastrophe resulting from recombinant influenza, in the hope that such a book would spur preparedness efforts:
Governments and individuals will do desperate things, some rational and others not so, like deploying the military to try to close borders or using firearms to keep possibly infected strangers at bay. Hospitals will be overwhelmed at first and later forced to lock their doors. To avoid interpersonal contact, people will hole up in their homes, causing government offices, schools, and businesses to close. Many public officials will be forced to quarantine themselves from a diseased population and retreat to undisclosed locations, which will only fuel the public panic. Riot police in biohazard suits (if there are even enough to go around) will increasingly be called upon to beat back waves of sick, scared, and helpless civilians, desperate for food, water, and medicine.
Tom Clancy seems to inspire a lot of our homeland security policy (though less so under the present Administration) — why shouldn’t Cook have a go at public health planning? Personally, I find the pandemic ‘flu threat more probable than terrorists armed with exploding water bottles.